The idea of the game is good, it has a lot of potential for something cool, but it was not well implemented, it has common mistakes from a beginner developer or short production time, but it is something that you will improve in the future, the controls work well, but the Movement is not well polished, making it very difficult to jump on platforms, and some jumps are almost impossible to get right. The way lava fills the map makes it impossible to complete the game if you're not extremely fast at the start.
Some things to help you improve the game or future projects:
Add coyote time (This will greatly improve jumping, and will allow for better precision and control of the character)
Adding double jump (this is something that, if used well, greatly enriches platform games, allowing you to create more elaborate platforms)
Because it is an hourglass, the lava can flow from the top to the bottom (this would differentiate the game from several others where the lava starts from the bottom to the top) the lava could flow through the corners of the hourglass and fill it.